Crude oil sample holding box for terahertz time domain spectroscopy system and method for detecting crude oil origin using terahertz detection chip

Abstract

The present invention provides a crude oil sample holding box for a terahertz time-domain spectroscopy system and a method for detecting the origin of crude oil using a terahertz detection chip. The crude oil sample holding box has the following characteristics, including: a box body, including a support plate and a containing plate connected to the support plate, the containing plate having a rectangular through groove for containing the crude oil sample and the terahertz detection chip; and a box cover, including a cover plate and a pressing plate connected to the cover plate, the pressing plate being adapted to the rectangular through groove and having a rectangular groove, the rectangular groove being used to contain the crude oil sample and the terahertz detection chip, when the box cover is placed on the box body, the pressing plate is located in the rectangular through groove, wherein the containing plate also has a plurality of first through holes evenly distributed around the rectangular through groove, the cover plate has a plurality of second through holes, the plurality of second through holes are arranged one-to-one with the plurality of first through holes, the second through holes cooperate with the corresponding first through holes and are screwed or pinned together.

Description

Technical Field

[0001] The present invention relates to the field of terahertz material detection, and in particular to a crude oil sample holding box for a terahertz time-domain spectroscopy system and a method for detecting the origin of crude oil using a terahertz detection chip. Background Art

[0002] Oil and gas resources are called "the blood of industry and play an important role in economic development and industrial modernization." In 2020, my country's crude oil imports reached 540 million tons, a year-on-year increase of 7.3%, making it the world's largest crude oil importer. Most of the trade in crude oil is completed by sea transportation. If a leak occurs and causes pollution and accountability, it is necessary to trace it. At present, the crude oil traceability technologies at home and abroad include: metal element identification technology, fluorescence spectroscopy (FS), infrared spectroscopy (IR), gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), isotope identification method (IRMS), etc. However, these detection technologies have many disadvantages: high technical requirements, cumbersome operation, expensive detection, not suitable for promotion, low sensitivity, need for preprocessing, and long data processing time.

[0003] In recent years, due to the development of photolithography and terahertz spectroscopy, research in the terahertz field has gradually emerged. Studies have shown that the two most important properties that determine the origin and properties of crude oil are its residual carbon content (measured by H / C ratio or aromaticity) and sulfur content (measured by unit mass fraction). Terahertz spectroscopy can distinguish different sulfur and residual carbon contents in crude oil components, and has the advantage of fast speed, but it requires a large amount of sample, and has poor signal-to-noise ratio and sensitivity.

[0004] The use of a time-domain terahertz spectroscopy system combined with a terahertz high-sensitivity detection chip can analyze the sulfur content and residual carbon content of crude oil in a very short time (<1s), thereby determining information such as the origin of the crude oil. It is a non-contact, rapid, and non-destructive detection method. It has a high signal-to-noise ratio, and the obtained spectral data has good repeatability and does not require preprocessing. This identification method reduces the tedious data processing process and can directly trace the type and origin of the oil product.

[0005] However, after the crude oil sample is dripped onto the terahertz high-sensitivity detection chip, it is not easy to transfer the two to the time-domain terahertz spectroscopy system. For example, during the transfer process, the crude oil sample may be displaced due to human manipulation by the operator, and the chip and the crude oil sample need to be transferred very carefully, which wastes time and easily leads to measurement errors. Summary of the invention

[0006] The present invention is made to solve the above-mentioned problem, and aims to provide a crude oil sample holding box for a terahertz time-domain spectroscopy system and a method for detecting the origin of crude oil using a terahertz detection chip.

[0007] The present invention provides a crude oil sample holding box for a terahertz time-domain spectroscopy system, which is used for holding the crude oil sample and a terahertz detection chip carrying the crude oil sample when the terahertz time-domain spectroscopy system is used to detect the crude oil sample. The box has the following characteristics, including: a box body, including a support plate and a containing plate connected to the support plate, the containing plate having a rectangular through groove for containing the crude oil sample and the terahertz detection chip; and a box cover, including a cover plate and a pressing plate connected to the cover plate, the pressing plate is adapted to the rectangular through groove and has a rectangular groove, the rectangular groove is used to contain the crude oil sample and the terahertz detection chip, when the box cover is placed on the box body, the pressing plate is located in the rectangular through groove, wherein the containing plate also has a plurality of first through holes evenly distributed around the rectangular through groove, the cover plate has a plurality of second through holes, the plurality of second through holes are arranged one-to-one with the plurality of first through holes, the second through holes cooperate with the corresponding first through holes and are screwed or pinned together.

[0008] The crude oil sample holding box for the terahertz time-domain spectroscopy system provided by the present invention may also have the following feature: wherein the depth of the rectangular groove is 0.05 mm to 1.25 mm.

[0009] The crude oil sample holding box for the terahertz time-domain spectroscopy system provided by the present invention may also have the following features: wherein the depth of the rectangular through groove is 4 mm to 4.2 mm, the length is 24 mm to 26 mm, the width is 21 mm to 23 mm, the length of the clamping plate is 23 mm to 25 mm, the width is 20 mm to 22 mm, and the height is equal to the depth of the rectangular through groove; when the clamping plate is located in the rectangular through groove, the length direction of the clamping plate is consistent with that of the rectangular through groove.

[0010] In the crude oil sample holding box for the terahertz time-domain spectroscopy system provided by the present invention, it can also have the following characteristics: wherein, the containing plate also has at least one indicating unit, the indicating unit is located on the central axis in the length direction of the rectangular through groove, and includes a first indicating groove and a second indicating groove, the first indicating groove is circular, the cover plate also has an indicating through hole corresponding to the first indicating groove, and the second indicating groove is rectangular, and its two ends are respectively connected to the first indicating groove and the rectangular through groove.

[0011] The crude oil sample containing box for the terahertz time-domain spectroscopy system provided by the present invention may also have the following features: wherein the containing plate has two indicating units, and the two indicating units are axially symmetrically distributed with the central axis of the width direction of the rectangular through slot as the axis.

[0012] The crude oil sample holding box for the terahertz time-domain spectroscopy system provided by the present invention may also have the following features: the rectangular through groove is located at the central position of the receiving plate, the clamping plate is located at the central position of the cover plate, the support plate and the receiving plate are integrally formed, the cover plate and the clamping plate are integrally formed, and the box body and the box cover are both made of polytetrafluoroethylene.

[0013] In the crude oil sample holding box for the terahertz time-domain spectroscopy system provided by the present invention, it can also have the following characteristics: wherein, the supersurface of the terahertz detection chip is a four-shaped double-split resonant ring structure, including a first connecting arm, a second connecting arm, a third connecting arm, a fourth connecting arm, a fifth connecting arm and a sixth connecting arm, the first connecting arm, the second connecting arm, the third connecting arm and the fourth connecting arm are parallel to each other, arranged in sequence and symmetrically distributed around the axis, the fifth connecting arm and the sixth connecting arm are respectively vertically connected to the two ends of the first connecting arm, the second connecting arm, the third connecting arm and the fourth connecting arm, and a through notch is provided in the middle of the first connecting arm and the fourth connecting arm.

[0014] In the crude oil sample holding box for the terahertz time-domain spectroscopy system provided by the present invention, it can also have the following characteristics: wherein, the size of the notch is L, L=3μm~5μm, the thickness of the first connecting arm, the second connecting arm, the third connecting arm, the fourth connecting arm, the fifth connecting arm and the sixth connecting arm are equal, which is D, D>L, and D=4μm~6μm, the spacing between the first connecting arm and the second connecting arm is 37μm~38μm, the spacing between the second connecting arm and the third connecting arm is 14.5μm~15.5μm, the length of the first connecting arm is 68μm~72μm, and the length of the fifth connecting arm and the sixth connecting arm is equal, which is 98μm~102μm.

[0015] The present invention provides a method for detecting the origin of crude oil using a terahertz detection chip, wherein the crude oil sample holding box for a terahertz time-domain spectroscopy system and the terahertz detection chip are used to detect the crude oil sample. The crude oil sample holding box includes a box body and a box cover, and has the following characteristics, including the following steps:

[0016] Step 1, pre-drying the detection environment of the terahertz spectroscopy analysis system;

[0017] Step 2, placing the terahertz detection chip in the box body, and then placing the box body in the center of the platform of the dried terahertz time-domain spectroscopy system;

[0018] Step 3, placing a piece of polycarbonate PC filter membrane in the box body and seamlessly fitting it above the terahertz detection chip, then covering the box cover on the box body and fixing the box cover and the box body, so that the terahertz pulse signal is vertically irradiated on the terahertz detection chip for detection, and obtaining a reference spectrum;

[0019] Step 4, taking out the crude oil sample box from the terahertz time-domain spectroscopy system, removing the box cover, and then using a pipette to transfer the crude oil sample and evenly apply it on the surface of the polycarbonate PC filter membrane;

[0020] Step 5, placing another polycarbonate PC filter membrane in the box body and covering the crude oil, then covering the box cover on the box body and fixing the box cover and the box body, placing the fixed crude oil sample holding box in the center of the platform of the terahertz time-domain spectroscopy system, so that the terahertz pulse signal is vertically irradiated on the terahertz detection chip for detection, and obtaining the detection spectrum of the crude oil sample;

[0021] Step 6: Subtract the reference spectrum from the detection spectrum to obtain the transmission spectrum of the crude oil sample.

[0022] The method for detecting the origin of crude oil by using a terahertz detection chip provided by the present invention may also have the following feature: wherein the thickness of the polycarbonate PC filter membrane is less than or equal to 0.5 μm.

[0023] Functions and Effects of the Invention

[0024] According to the crude oil sample holding box for a terahertz time-domain spectroscopy system involved in the present invention, because it includes a box body and a box cover, the box body includes a containing plate, the containing plate has a rectangular through groove for containing the crude oil sample and the terahertz detection chip; the box cover has a cover plate and a pressing plate connected to the cover plate, the pressing plate is adapted to the rectangular through groove and has a rectangular groove, when the box cover is placed on the box body, the pressing plate is located in the rectangular through groove; therefore, the terahertz detection chip carrying the crude oil sample can be placed in the space formed by the rectangular groove and the rectangular through groove, thereby preventing the problem of displacement in the process of transferring the terahertz detection chip carrying the crude oil sample to the terahertz time-domain spectroscopy system, and can shorten the time spent on the transfer.

[0025] In addition, because the accommodating plate is also provided with a plurality of first through holes evenly distributed around the rectangular through groove, the cover plate is also provided with a plurality of second through holes, and the plurality of second through holes are arranged one-to-one correspondingly to the plurality of first through holes, and the second through holes cooperate with the corresponding first through holes and are screwed or pinned together. This can make the fixation of the box body and the box cover more secure and reduce the possibility of displacement of the crude oil sample during movement. On the other hand, it can easily realize the fixation or separation of the box body and the box cover, which is very convenient to use.

[0026] According to the method for detecting the origin of crude oil by using a terahertz detection chip involved in the present invention, since the above-mentioned crude oil sample holding box is used to hold the crude oil sample and the terahertz detection chip, the detection result is more accurate and reliable, and because when placing the crude oil sample and the terahertz detection chip in the crude oil sample holding box, the terahertz detection chip is first placed in the box body, and then a polycarbonate PC filter membrane is placed, and then the crude oil sample is dripped, and then another polycarbonate PC filter membrane is placed, and finally the box cover is put on and fixed, the two polycarbonate PC filter membranes can protect the terahertz detection chip from being contaminated by crude oil. Compared with the case where no PC filter membrane is set, the detection result of the method of the present invention has a smaller amplitude, a wider bandwidth, a smaller red shift, a higher detection signal-to-noise ratio, a higher sensitivity and a lower detection limit, and less signal loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic front view of a crude oil sample holding box in the first embodiment of the present invention;

[0028] Figure 2 is a side view schematic diagram of a crude oil sample holding box in the first embodiment of the present invention;

[0029] Figure 3 is a schematic diagram of the three-dimensional structure of the box body in the first embodiment of the present invention;

[0030] Figure 4 is a side view schematic diagram of the box body in the first embodiment of the present invention;

[0031] Figure 5 is a schematic diagram of the three-dimensional structure of the box cover in the first embodiment of the present invention;

[0032] Figure 6 It is a side view schematic diagram of the box cover in the first embodiment of the present invention.

[0033] Figure 7 is a schematic structural diagram of a terahertz detection chip in Embodiment 1 of the present invention;

[0034] Figure 8 is a flow chart of a method for detecting the origin of crude oil using a terahertz detection chip in Embodiment 1 of the present invention;

[0035] Fig. 9 It is a schematic diagram of stacking a crude oil sample in a crude oil sample holding box 100 in a method for detecting the origin of crude oil by using a terahertz detection chip in Embodiment 1 of the present invention;

[0036] Fig.10 This is a photograph of the process of placing a crude oil sample in the containing box 100 in the method of detecting the origin of crude oil by using a terahertz detection chip in the first embodiment of the present invention;

[0037] Fig.11 are photos of 12 crude oil samples from different origins in Example 2 of the present invention; Fig.12 This is the experimental transmission spectrum of 12 crude oil samples from different origins in Example 2 of the present invention;

[0038] Fig.13 The frequency shift point diagram and the linear fitting diagram in the second embodiment of the present invention; and

[0039] Fig.14 It is a bar graph showing the relationship between the full frequency shift and the single frequency shift in the mixture in the second embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments and the accompanying drawings specifically illustrate the crude oil sample holding box used in the terahertz time-domain spectroscopy system of the present invention and the method of detecting the origin of crude oil using a terahertz detection chip.

[0041] <Example 1>

[0042] Embodiment 1 provides a crude oil sample holding box for a terahertz time-domain spectroscopy system and a method for detecting the origin of crude oil using a terahertz detection chip.

[0043] Figure 1 is a schematic front view of a crude oil sample holding box in the first embodiment of the present invention; Figure 2 It is a schematic side view of a crude oil sample holding box in the first embodiment of the present invention.

[0044] like Figure 1 and Figure 2 As shown, the crude oil sample holding box 100 in the first embodiment includes a box body 10, a box cover 20 and a connecting piece (not shown in the figure). The crude oil sample holding box 100 is used to hold the crude oil sample and the terahertz detection chip carrying the crude oil sample when the terahertz time-domain spectroscopy system is used to detect the crude oil sample.

[0045] Figure 3 is a schematic diagram of the three-dimensional structure of the box body in the first embodiment of the present invention; Figure 4 It is a side view schematic diagram of the box body in the first embodiment of the present invention.

[0046] like Figure 3 and Figure 4 As shown, the box body 10 includes a supporting plate 11 and a receiving plate 12 .

[0047] The support plate 11 plays a supporting role and is a rectangular parallelepiped with a length of 56 mm and a width of 50 mm.

[0048] The receiving plate 12 is fixedly connected to the upper surface of the supporting plate 11. The receiving plate 12 is a rectangular parallelepiped, and its length and width are both 50 mm, and its height is 4 mm.

[0049] The central position of the receiving plate 12 has a rectangular through slot 121 that penetrates the receiving plate 12. The length direction of the rectangular through slot 121 is consistent with the length direction of the supporting plate 11, and is 25 mm long, 22 mm wide, and 4 mm deep.

[0050] like Figures 1 to 4 As shown, the receiving plate 12 also has 8 first through holes 122. The 8 first through holes 122 are evenly distributed around the rectangular through slot 121, and each side of the receiving plate 12 is provided with 2 first through holes 122. The support plate 11 also has 8 third through holes 111 that are adapted to the first through holes 122 and are arranged one by one.

[0051] The receiving plate 12 also has two indicating units 123. The indicating units 123 are located at the central axis ( Figure 4 The first indicator groove 1231 and the second indicator groove 1232 are arranged on the dotted line L in the figure. The first indicator groove 1231 is a circular groove. The second indicator groove 1232 is a rectangular groove, and its two ends are respectively connected to the first indicator groove 1231 and the rectangular through groove 121. The first indicator groove 1231 and the second indicator groove 1232 are both used to indicate the placement position of the terahertz detection chip. The two indicator units 123 are axially symmetrically distributed with the central axis of the width direction of the rectangular through groove 121 as the axis.

[0052] The support plate 11 and the receiving plate 12 are integrally formed, and the material of the box body 10 is polytetrafluoroethylene.

[0053] Figure 5 is a schematic diagram of the three-dimensional structure of the box cover in the first embodiment of the present invention; Figure 6 It is a side view schematic diagram of the box cover in the first embodiment of the present invention.

[0054] like Figure 5 and Figure 6 As shown, the box cover 20 includes a cover plate 21 and a pressing plate 22 .

[0055] The pressing plate 22 is connected to the cover plate 21 and is located at the center of the cover plate 21. The pressing plate 22 is in the shape of a cuboid, with a length of 24 mm, a width of 21 mm, and a height of 9 mm. The pressing plate 22 is adapted to the rectangular through slot 121.

[0056] The clamping plate 22 has a rectangular groove 221, which runs through the two sides of the clamping plate 22 along the length direction of the clamping plate 22. The rectangular groove 221 is used to accommodate the crude oil sample and the terahertz detection chip. The depth of the rectangular groove 221 is 0.05mm to 1.25mm. Specifically, the depth of the rectangular groove 221 can be set to any one of 0.05mm, 0.1mm, 0.25mm, 0.5mm, 1mm and 1.25mm as needed. In this embodiment, the depth of the rectangular groove 221 is 0.5mm.

[0057] Figure 7 is a schematic structural diagram of a terahertz detection chip in Embodiment 1 of the present invention;

[0058] like Figure 7 As shown, the terahertz detection chip 1 used in this embodiment is a four-shaped double-split resonant ring structure chip designed based on the double-ring magnetic field effect. The super surface of the terahertz detection chip 1 is a four-shaped double-split resonant ring structure, including a first connecting arm 2, a second connecting arm 3, a third connecting arm 4, a fourth connecting arm 5, a fifth connecting arm 6 and a sixth connecting arm 7. The first connecting arm 2, the second connecting arm 3, the third connecting arm 4 and the fourth connecting arm 5 are parallel to each other, arranged in sequence and symmetrically distributed in the axis center. The fifth connecting arm 6 and the sixth connecting arm 7 are respectively connected perpendicularly to the two ends of the first connecting arm 2, and the fifth connecting arm 6 and the sixth connecting arm 7 are also respectively connected perpendicularly to the two ends of the second connecting arm 3, and the fifth connecting arm 6 and the sixth connecting arm 7 are also respectively connected perpendicularly to the two ends of the third connecting arm 4, and the fifth connecting arm 6 and the sixth connecting arm 7 are also respectively connected perpendicularly to the two ends of the fourth connecting arm 5. A through notch 8 is provided in the center of the first connecting arm 2 and the fourth connecting arm 5.

[0059] The size of the notch 8 is L, L=3 μm to 5 μm, and in this embodiment, L=4 μm.

[0060] The thicknesses of the first connecting arm 2 , the second connecting arm 3 , the third connecting arm 4 , the fourth connecting arm 5 , the fifth connecting arm 6 and the sixth connecting arm 7 are equal, namely D, D>L, and D=4μm~6μm. In this embodiment, L=5μm.

[0061] The spacing between the first connecting arm 2 and the second connecting arm 3 is 37μm to 38μm. In this embodiment, the spacing between the first connecting arm 2 and the second connecting arm 3 is L=37.5μm. The spacing between the second connecting arm 3 and the third connecting arm 4 is 14.5μm to 15.5μm. In this embodiment, the spacing between the second connecting arm 3 and the third connecting arm 4 is 15μm. The length of the first connecting arm 2 is 68μm to 72μm. In this embodiment, the length of the first connecting arm 2 is 70μm. The lengths of the fifth connecting arm 6 and the sixth connecting arm 7 are equal, which are 98μm to 102μm. In this embodiment, the lengths of the fifth connecting arm 6 and the sixth connecting arm 7 are both 100μm.

[0062] The terahertz detection chip 1 of the present embodiment has a high quality factor to effective mode volume ratio and a short relaxation time, and is very suitable for high-sensitivity detection applications.

[0063] like Figure 2 , Figure 5 as well as Figure 6 As shown, the cover plate 21 has eight second through holes 211, and the eight second through holes are arranged one by one with the eight first through holes 122. The second through holes 211 match with the corresponding first through holes and are screwed or pinned together. This embodiment is pinned.

[0064] like Figure 5 as well as Figure 6 As shown, the cover plate 21 also has two indicating through holes 212. The indicating through holes 212 penetrate the upper surface and the lower surface of the cover plate 21. The two indicating through holes 212 are arranged in a one-to-one correspondence with the two first indicating grooves 1231, and the indicating through holes 212 match the shapes and sizes of the first indicating grooves 1231.

[0065] The cover plate 21 and the pressing plate 22 are integrally formed, and the material of the box cover 20 is polytetrafluoroethylene.

[0066] When the box cover 20 is placed on the box body 10, the pressing plate 22 is located in the rectangular through slot 121, and the length direction of the pressing plate 22 is consistent with the length direction of the rectangular through slot 121. At this time, the indicating through hole 212 is aligned and overlapped with the first indicating slot 1231, the second indicating slot 1232 is blocked by the cover plate 21, and the second through hole 211, the first through hole 122 and the third through hole 111 are aligned and overlapped from top to bottom. At this time, the box cover 20 and the box body 10 can be fixed by passing the connecting member (a pin in this embodiment) through the second through hole 211, the first through hole 122 and the third through hole 111.

[0067] Figure 8 is a flow chart of a method for detecting the origin of crude oil using a terahertz detection chip in Embodiment 1 of the present invention; Fig. 9It is a schematic diagram of stacking a crude oil sample in a crude oil sample holding box 100 in a method for detecting the origin of crude oil by using a terahertz detection chip in Embodiment 1 of the present invention; Fig.10 This is a photograph of the process of placing a crude oil sample in a containing box 100 in the method for detecting the origin of crude oil by using a terahertz detection chip in the first embodiment of the present invention.

[0068] like Figures 8 to 10 As shown, the method for detecting the origin of crude oil by using the terahertz detection chip 1 and the crude oil sample holding box 100 in this embodiment includes the following steps:

[0069] Step 1, pre-dry the detection environment of the terahertz spectroscopy analysis system. The detection method of the terahertz time-domain spectroscopy system is transmission detection. The process of the drying pre-treatment in step 1 is: before the experiment, the water vapor inside the system is removed by a dry air filtration unit, and the humidity is monitored in real time with a hygrometer until the humidity is lower than 3%.

[0070] Step 2: Place the terahertz detection chip 1 in the box body 10, and then place the box body 10 in the center of the platform of the dried terahertz time-domain spectroscopy system.

[0071] Step 3, place a piece of polycarbonate PC filter (referred to as filter No. 1) in the box body 10, above the terahertz detection chip 1 and seamlessly fit the terahertz detection chip 1, then cover the box cover 20 on the box body 10 and fix the box cover 20 and the box body 10, so that the terahertz pulse signal is vertically irradiated on the terahertz detection chip 1 for detection, and obtain a reference spectrum. The filter membrane No. 1 has a diameter of 25 mm, a thickness of 0.4 μm, and a refractive index of 1.6.

[0072] Step 4, take out the crude oil sample box 100 from the terahertz time-domain spectroscopy system, remove the box cover 20, and then use a pipette to transfer a volume of 1.2 dL of crude oil sample and evenly apply it on the surface of filter membrane No. 1. The thickness of the crude oil sample coated on filter membrane No. 1 is 24 μm. When dripping the crude oil sample, drip it according to the position indicated by the second indicator groove 1232 of the box body 10.

[0073] Step 5, place another piece of polycarbonate PC filter membrane (referred to as filter membrane No. 2) in the box body and cover the crude oil, so that the terahertz detection chip 1, filter membrane No. 1, crude oil sample, and filter membrane No. 2 are seamlessly attached in sequence from bottom to top, and then cover the box cover 20 on the box body 10 and fix the box cover 20 and the box body 10, and place the fixed crude oil sample holding box 100 in the center of the platform of the terahertz time-domain spectroscopy system (the alignment of this position needs to be confirmed according to the position of the indicating through hole 212 of the box cover 20), so that the terahertz pulse signal is vertically irradiated on the terahertz detection chip 1 for detection, and the detection spectrum of the crude oil sample is obtained. When the terahertz pulse signal is irradiated vertically, it will be vertically irradiated on the seamlessly attached box body 10, the terahertz detection chip 1, filter membrane No. 1, the crude oil sample, filter membrane No. 2 and the box cover 20 (see Fig. 9 ), and then the signal receiving end of the terahertz spectroscopy analysis system receives the transmitted pulse signal and performs signal processing to obtain the detection spectrum.

[0074] Step 6, subtract the reference spectrum from the detection spectrum to obtain the transmission spectrum of the crude oil sample. By comparing the detection spectrum with the reference spectrum, the drift of the inherent resonance frequency of the terahertz detection chip 1 caused by different crude oil samples is found. Finally, the different drift values ​​of the inherent resonance frequency generated by crude oils with different sulfur contents and different H / C ratios are compared to obtain the sulfur content and residual carbon value of the crude oil sample, and determine the properties and origin of the crude oil.

[0075] Functions and Effects of Embodiment 1

[0076] According to the crude oil sample holding box for the terahertz time-domain spectroscopy system involved in the first embodiment, because it includes a box body and a box cover, the box body includes a containing plate, the containing plate has a rectangular through groove for containing the crude oil sample and the terahertz detection chip; the box cover has a cover plate and a clamping plate connected to the cover plate, the clamping plate is adapted to the rectangular through groove and has a rectangular groove, when the box cover is placed on the box body, the clamping plate is located in the rectangular through groove; therefore, the terahertz detection chip carrying the crude oil sample can be placed in the space formed by the rectangular groove and the rectangular through groove, thereby preventing the displacement problem in the process of transferring the terahertz detection chip carrying the crude oil sample to the terahertz time-domain spectroscopy system, and can shorten the time spent on the transfer.

[0077] In addition, because the accommodating plate of the first embodiment is also provided with a plurality of first through holes evenly distributed around the rectangular through groove, the cover plate is also provided with a plurality of second through holes, and the plurality of second through holes are arranged one-to-one with the plurality of first through holes, and the second through holes cooperate with the corresponding first through holes and are screwed or pinned together. This can make the fixation of the box body and the box cover more secure and reduce the possibility of displacement of the crude oil sample during movement. On the other hand, it can easily realize the fixation or separation of the box body and the box cover, which is very convenient to use.

[0078] Furthermore, the depth of the rectangular groove is 0.05 mm to 1.25 mm, which can meet the needs of placing crude oil samples and terahertz detection chips during actual detection.

[0079] Furthermore, the depth of the rectangular through groove is 4mm~4.2mm, the length is 24mm~26mm, the width is 21mm~23mm, the length of the clamping plate is 23mm~25mm, the width is 20mm~22mm, and the height is equal to the depth of the rectangular through groove. When the clamping plate is located in the rectangular through groove, the length direction of the clamping plate is consistent with that of the rectangular through groove. Such an arrangement can meet the needs of crude oil sample detection.

[0080] Furthermore, the containing plate also has at least two indicating units, which are located on the central axis of the length direction of the rectangular through slot, and have a first indicating slot and a second indicating slot. Through the indication of the second indicating slot, the filter membrane and the original sample can be accurately placed in the rectangular through slot and located on the central axis of the length direction of the rectangular through slot. The cover plate also has an indicating through hole corresponding to the first indicating slot. When the crude oil sample is placed in the box body 10 and the box cover 20 is closed, the crude oil drop position can also be confirmed through the indicating through hole, so that the crude oil sample holding box 100 can be placed in a position where the sample can be vertically irradiated by the terahertz pulse signal. This can make the measurement result more accurate.

[0081] Furthermore, the support plate and the containing plate are integrally formed, the cover plate and the pressing plate are integrally formed, and the box body and the box cover are both made of polytetrafluoroethylene, which can prevent the crude oil sample containing box from causing adverse interference to the terahertz detection of petroleum.

[0082] According to the method for detecting the origin of crude oil by using a terahertz detection chip involved in Example 1, since the above-mentioned crude oil sample holding box is used to hold the crude oil sample and the terahertz detection chip, the detection result is more accurate and reliable, and since the method first places the terahertz detection chip in the box body when placing the crude oil sample and the terahertz detection chip in the crude oil sample holding box, and then places a polycarbonate PC filter membrane, and then drops the crude oil sample, and then places another polycarbonate PC filter membrane, and finally covers the box and fixes it, the two polycarbonate PC filter membranes can protect the terahertz detection chip from being contaminated by crude oil. Compared with the case where no PC filter membrane is set, the detection result of the method of the present invention has a smaller amplitude, a wider bandwidth, a smaller red shift, a higher detection signal-to-noise ratio, a higher sensitivity and a lower detection limit, and less signal loss.

[0083] In addition, the method of Example 1 is used to detect crude oil, which simplifies the detection process, reduces the number and complexity of test data, and improves the practicality of the terahertz high-sensitivity detection chip for detecting crude oil. The detection requires less sample and the detection time is short, which can achieve fast, accurate, trace and real-time spectral detection.

[0084] <Example 2>

[0085] This embodiment adopts the method of detecting the origin of crude oil by using a terahertz detection chip in the first embodiment and uses a crude oil sample holding box 100 to detect 12 kinds of crude oil samples from different origins.

[0086] The specific detection process of Example 2 is as follows:

[0087] Step 1: pre-dry the detection environment of the terahertz spectroscopy analysis system.

[0088] Step 2: Place the terahertz detection chip 1 in the box body 10, and then place the box body 10 in the center of the platform of the dried terahertz time-domain spectroscopy system.

[0089] Step 3, place a piece of polycarbonate PC filter (referred to as filter No. 1) in the box body 10, above the terahertz detection chip 1 and seamlessly fit the terahertz detection chip 1, then cover the box cover 20 on the box body 10 and fix the box cover 20 and the box body 10, so that the terahertz pulse signal is vertically irradiated on the terahertz detection chip 1 for detection, and obtain a reference spectrum. The filter membrane No. 1 has a diameter of 25 mm, a thickness of 0.4 μm, and a refractive index of 1.6.

[0090] Step 4: Take the crude oil sample box 100 out of the terahertz time-domain spectroscopy system, remove the box cover 20, and then use a pipette to transfer 1.2 dL of crude oil sample and evenly apply it on the surface of filter membrane No. 1. The thickness of the crude oil sample applied on filter membrane No. 1 is 24 μm.

[0091] Step 5, place another polycarbonate PC filter membrane (referred to as filter membrane No. 2) in the box body and cover the crude oil, so that the terahertz detection chip 1, filter membrane No. 1, crude oil sample, and filter membrane No. 2 are seamlessly fitted in sequence from bottom to top, and then the box cover 20 is covered on the box body 10 and the box cover 20 and the box body 10 are fixed, and the fixed crude oil sample holding box 100 is placed in the center of the platform of the terahertz time-domain spectroscopy system, so that the terahertz pulse signal is vertically irradiated on the terahertz detection chip 1 for detection, and the detection spectrum of the crude oil sample is obtained.

[0092] Step 6, subtract the reference spectrum from the detection spectrum to obtain the transmission spectrum of the crude oil sample. By comparing the detection spectrum with the reference spectrum, the drift of the inherent resonance frequency of the terahertz detection chip 1 caused by different crude oil samples is found. Finally, the different drift values ​​of the inherent resonance frequency generated by crude oils with different sulfur contents and different H / C ratios are compared to obtain the sulfur content and residual carbon value of the crude oil sample, and determine the properties and origin of the crude oil.

[0093] Step 7, repeat steps 2 to 6 to test the other 11 crude oil samples, and to ensure the accuracy of the measurement, a new polycarbonate PC filter membrane needs to be replaced each time a different sample is tested.

[0094] Fig.11 are photos of 12 crude oil samples from different origins in Example 2 of the present invention; Fig.12 This is the experimental transmission spectrum of the detection of 12 crude oil samples from different origins in Example 2 of the present invention.

[0095] like Fig.12 As shown in the figure, the 12 curves represent one of the 12 crude oil samples from different origins. The horizontal axis represents the frequency and the vertical axis represents the transmittance (dB). Fig.12 It can be seen that with the change of the origin of the crude oil samples, the sulfur content and residual carbon in the crude oil also change, so that the refractive index will change. From the No. 2-2 crude oil sample to the No. 9-5 crude oil sample, the amplitude becomes significantly larger, the bandwidth becomes significantly wider, and the resonance frequency undergoes a certain blue shift.

[0096] Fig.13 This is a frequency shift point diagram and a linear fitting diagram in the second embodiment of the present invention, wherein: Fig.13 (a) is the frequency shift point diagram and linear fitting diagram of sulfur content, Fig.13 (b) is the frequency shift point diagram and linear fitting diagram of residual carbon content.

[0097] like Fig.13 As shown in (a), the frequency shift depends on the sulfur content and the carbon residue content in the sample. When the sulfur content is higher than 3%, it can be observed that the frequency shift changes slowly, and the frequency shift is about 40GHz. When the sulfur content is higher than 7%, it can be observed that the frequency shift changes slowly, and the frequency shift is about 50GHz. Fig.13 (b) The residual carbon value in the sample is low, indicating that its main components are low-ring aromatic hydrocarbons.

[0098] Fig.14 It is a bar graph showing the relationship between the full frequency shift and the single frequency shift in the mixture in the second embodiment of the present invention.

[0099] like Fig.14As shown, the frequency shift of crude oil mixing is equivalent to the superposition of the frequency shifts of individual components in each group, where R is the percentage deviation between the calculated results and the experimental results.

[0100] Functions and Effects of Embodiment 2

[0101] The detection of Example 2 shows that the method of Example 1 can more accurately change the sulfur content and residual carbon in the crude oil sample, so that the refractive index will change. From the No. 2-2 crude oil sample to the No. 9-5 crude oil sample, the amplitude is significantly increased, the bandwidth is significantly widened, and the resonance frequency has a certain blue shift. The measured spectrum is very stable, so it can effectively distinguish crude oils from different sources.

[0102] The above-mentioned embodiments are preferred examples of the present invention and are not intended to limit the protection scope of the present invention.

Claims

1. A crude oil sample holding box for a terahertz time-domain spectroscopy system, used to hold the crude oil sample and a terahertz detection chip carrying the crude oil sample when the crude oil sample is detected by the terahertz time-domain spectroscopy system, characterized in that: include: A box body, comprising a support plate and a receiving plate connected to the support plate, wherein the receiving plate has a rectangular through groove for receiving the crude oil sample and the terahertz detection chip; as well as The box cover comprises a cover plate and a pressing plate connected to the cover plate, wherein the pressing plate is adapted to the rectangular through groove and has a rectangular groove for accommodating the crude oil sample and the terahertz detection chip. When the box cover is placed on the box body, the pressing plate is located in the rectangular through groove. The receiving plate further has a plurality of first through holes evenly distributed around the rectangular through slot. The cover plate has a plurality of second through holes, and the plurality of second through holes are arranged one by one corresponding to the plurality of first through holes, and the second through holes are matched with the corresponding first through holes and are screwed or pinned together. The receiving plate also has at least one indicating unit, The indicating unit is located on the central axis of the rectangular through groove in the length direction, and includes a first indicating groove and a second indicating groove. The first indicating groove is circular, and the cover plate also has an indicating through hole corresponding to the first indicating groove. The second indicating groove is rectangular, and its two ends are respectively connected to the first indicating groove and the rectangular through groove.

2. The crude oil sample holding box for the terahertz time-domain spectroscopy system according to claim 1, characterized in that: in, The depth of the rectangular groove is 0.05 mm to 1.25 mm.

3. The crude oil sample holding box for the terahertz time-domain spectroscopy system according to claim 1, characterized in that: in, The rectangular through groove has a depth of 4 mm to 4.2 mm, a length of 24 mm to 26 mm, and a width of 21 mm to 23 mm. The length of the clamping plate is 23mm~25mm, the width is 20mm~22mm, and the height is equal to the depth of the rectangular through groove. When the pressing plate is located in the rectangular through slot, the length direction of the pressing plate is consistent with that of the rectangular through slot.

4. The crude oil sample holding box for the terahertz time-domain spectroscopy system according to claim 1, characterized in that: in, The accommodating plate has two indicating units, and the two indicating units are axially symmetrically distributed with the central axis of the width direction of the rectangular through slot as an axis.

5. The crude oil sample holding box for the terahertz time-domain spectroscopy system according to claim 1, characterized in that: in, The rectangular through slot is located at the center of the receiving plate. The pressing plate is located at the center of the cover plate. The support plate and the receiving plate are integrally formed, and the cover plate and the pressing plate are integrally formed. The box body and the box cover are both made of polytetrafluoroethylene.

6. The crude oil sample holding box for the terahertz time-domain spectroscopy system according to claim 1, characterized in that: in, The metasurface of the terahertz detection chip is a four-shaped double-split resonant ring structure, including a first connecting arm, a second connecting arm, a third connecting arm, a fourth connecting arm, a fifth connecting arm and a sixth connecting arm, wherein the first connecting arm, the second connecting arm, the third connecting arm and the fourth connecting arm are parallel to each other, arranged in sequence and symmetrically distributed along the axis, and the fifth connecting arm and the sixth connecting arm are respectively vertically connected to two ends of the first connecting arm, the second connecting arm, the third connecting arm and the fourth connecting arm. A through notch is provided in the middle of the first connecting arm and the fourth connecting arm.

7. The crude oil sample holding box for the terahertz time-domain spectroscopy system according to claim 6, characterized in that: in, The size of the gap is L, L=3μm~5μm, The thicknesses of the first connecting arm, the second connecting arm, the third connecting arm, the fourth connecting arm, the fifth connecting arm and the sixth connecting arm are equal, which is D, D>L, and D=4μm~6μm, The distance between the first connecting arm and the second connecting arm is 37 μm to 38 μm. The distance between the second connecting arm and the third connecting arm is 14.5 μm to 15.5 μm. The length of the first connecting arm is 68 μm to 72 μm, The length of the fifth connecting arm is equal to that of the sixth connecting arm, which is 98 μm to 102 μm.

8. A method for detecting the origin of crude oil using a terahertz detection chip, using the crude oil sample holding box for a terahertz time-domain spectroscopy system and the terahertz detection chip as described in any one of claims 1 to 7 to detect the crude oil sample, wherein the crude oil sample holding box comprises a box body and a box cover, and has the following characteristics, the method comprising the following steps: Step 1, pre-drying the detection environment of the terahertz spectroscopy analysis system; Step 2, placing the terahertz detection chip in the box body, and then placing the box body in the center of the platform of the dried terahertz time-domain spectroscopy system; Step 3, placing a piece of polycarbonate PC filter membrane in the box body and seamlessly fitting it above the terahertz detection chip, then covering the box cover on the box body and fixing the box cover and the box body, so that the terahertz pulse signal is vertically irradiated on the terahertz detection chip for detection, and obtaining a reference spectrum; Step 4, taking the crude oil sample holding box out of the terahertz time-domain spectroscopy system, removing the box cover, and then using a pipette to transfer the crude oil sample and evenly apply it on the surface of the polycarbonate PC filter membrane; Step 5, placing another polycarbonate PC filter membrane in the box body and covering the crude oil, then covering the box cover on the box body and fixing the box cover and the box body, placing the fixed crude oil sample holding box in the center of the platform of the terahertz time-domain spectroscopy system, so that the terahertz pulse signal is vertically irradiated on the terahertz detection chip for detection, and obtaining the detection spectrum of the crude oil sample; Step 6: subtract the reference spectrum from the detection spectrum to obtain the transmission spectrum of the crude oil sample.

9. The method for detecting the origin of crude oil using a terahertz detection chip according to claim 8, characterized in that: in, The thickness of the polycarbonate PC filter membrane is less than or equal to 0.5 μm.

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